Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 8Citation - Scopus: 8Involvement of Sphingolipid Metabolism Enzymes in Resveratrol-Mediated Cytotoxicity in Philadelphia-Positive Acute Lymphoblastic Leukemia(Routledge Journals, Taylor & Francis Ltd, 2021-11-22) Oguz, Osman; Adan, AysunTargeting the key enzymes of sphingolipid metabolism including serine palmitoyltransferase (SPT), sphingosine kinase (SK) and glucosylceramide synthase (GCS) has a therapeutic importance. However, sphingolipid metabolism-mediated anti-leukemic actions of resveratrol in Philadelphia-positive acute lymphoblastic leukemia (Ph + ALL) remain unknown. Therefore, we explored potential mechanisms behind resveratrol-mediated cytotoxicity in SD1 and SUP-B15 Ph + ALL cells in the context of sphingolipid metabolism and apoptosis induction. The anti-proliferative and apoptotic effects of resveratrol alone and in combination with SPT inhibitor (myriocin), SK inhibitor (SKI II), GCS inhibitor (PDMP) were determined by MTT cell proliferation assay and flow cytometry, respectively. The effects of resveratrol on PARP cleavage, SPT, SK and GCS protein levels were investigated by Western blot. Resveratrol inhibited proliferation and triggered apoptosis via PARP activation and externalization of phosphatidylserine (PS). Resveratrol increased the expression of SPT whereas it downregulated SK and GCS. Resveratrol's combinations with SKI II and PDMP intensified its anti-leukemic activity by increasing the relocalization of PS while its combination with myriocin suppressed apoptosis. Therefore, resveratrol inhibited cell proliferation and induced apoptosis through modulating SK, GCS and SPT expression, which may be considered as novel biomarkers of resveratrol-induced cytotoxicity in Ph + ALL.Article Functional Combination of Resveratrol and Midostaurin Induces Cytotoxicity to Overcome Acquired Midostaurin Resistance in FLT3-ITD Expressing Acute Myeloid Leukemia Cells(Springer, 2025-08-20) Tecik, Melisa; Adan, AysunThe most important challenge in treating FLT3-ITD AML is the development of resistance to FLT3 inhibitors, such as midostaurin, via both FLT3-dependent and FLT3-independent mechanisms. The study explored the potential cytotoxic effects of combining resveratrol and midostaurin on the sensitization of midostaurin-resistant cells. MTT assay revealed resveratrol's chemo-sensitizing influence on midostaurin-resistant cells, and combination indexes (CI) were calculated using Chou-Talalay's method. Apoptosis induction and cell cycle progression was analyzed by flow cytometry. The apoptotic molecular markers caspase 3, PARP, Bcl-2, and Bax were analyzed using a western blot. Sphingosine kinase-1 (SK-1) expression, total and phosphorylated FLT3, and STAT5A levels were measured using western blotting. Resveratrol enhanced the cytotoxic effects of midostaurin additively in resistant MV4-11MR and MOLM-13MR cells. It effectively reversed midostaurin resistance by inhibiting the activating phosphorylation of FLT3, STAT5A, and modulating the expression of SK-1 while concurrently increasing the levels of cleaved caspase-3 and PARP without noticeable alterations in Bax/Bcl-2 ratios except MV4-11MR cells. Additionally, there was an arrest at the S or G0/G1 phase of the cell cycle, depending on the resistant cells, compared to midostaurin alone, but not to the control group. In conclusion, the FLT3/STAT5A axis and SK-1 might play an important role in the reversal of midostaurin resistance by resveratrol. Therefore, the concurrent administration of resveratrol plus midostaurin could potentially serve as a therapeutic approach to address midostaurin resistance and enhance the overall therapy efficacy for FLT3-ITD AML patients after being validated with future in vivo and ex vivo studies.Article Citation - WoS: 446Citation - Scopus: 493Cell Proliferation and Cytotoxicity Assays(Bentham Science Publ Ltd, 2016-11-11) Adan, Aysun; Kiraz, Yagmur; Baran, YusufCell viability is defined as the number of healthy cells in a sample and proliferation of cells is a vital indicator for understanding the mechanisms in action of certain genes, proteins and pathways involved cell survival or death after exposing to toxic agents. Generally, methods used to determine viability are also common for the detection of cell proliferation. Cell cytotoxicity and proliferation assays are generally used for drug screening to detect whether the test molecules have effects on cell proliferation or display direct cytotoxic effects. Regardless of the type of cell-based assay being used, it is important to know how many viable cells are remaining at the end of the experiment. There are a variety of assay methods based on various cell functions such as enzyme activity, cell membrane permeability, cell adherence, ATP production, co-enzyme production, and nucleotide uptake activity. These methods could be basically classified into different categories: (I) dye exclusion methods such as trypan blue dye exclusion assay, (II) methods based on metabolic activity, (III) ATP assay, (IV) sulforhodamine B assay, (V) protease viability marker assay, (VI) clonogenic cell survival assay, (VII) DNA synthesis cell proliferation assays and (V) raman micro-spectroscopy. In order to choose the optimal viability assay, the cell type, applied culture conditions, and the specific questions being asked should be considered in detail. This particular review aims to provide an overview of common cell proliferation and cytotoxicity assays together with their own advantages and disadvantages, their methodologies, comparisons and intended purposes.